Type Ia Supernova Explosions in Binary Systems: The Impact on the Secondary Star and Its Consequences

Abstract

One method of discriminating between the many Type Ia progenitor scenarios is by searching for contaminating hydrogen and helium stripped from the companion star. However, this requires understanding the effect of the impact of the supernova shell on different companion stars to predict the amount of mass stripped and its distribution in velocity and solid angle for the types of binary scenarios that have been proposed as Type Ia progenitor models.We present several high-resolution 2-D numerical simulations of the impact of a Type Ia supernova explosion with hydrogen-rich main sequence, subgiant, and red giant companions. The binary parameters were chosen to represent several classes of single-degenerate Type Ia progenitor models that have been suggested in the literature. We use realistic stellar models and supernova debris profiles to represent each binary system. For each scenario, we explore the hydrodynamics of the supernova-secondary interaction, calculate the amount of stellar material stripped from the secondary and the kick delivered by the impact, and construct the velocity and solid angle distributions of the stripped material.We find that the main sequence and subgiant companions lose 0.15 − 0.17 M ⊙ as a result of the impact of the supernova shell, 15% of their mass. The red giant companions lose 0.53 − 0.54 M ⊙ , 96% − 98% of their envelopes. The characteristic velocity of the stripped hydrogen is less than 10 3 km s −1 for all the scenarios: 420 − 590 km s −1 for the red giant companions, 820 km s −1 for the main sequence companion, and 890 km s −1 for the subgiant companion. The stripped hydrogen and helium contaminate a wide solid angle behind the companion: 115 • from the downstream axis for the red giant, 66 • for the main sequence star, and 72 • for the subgiant. With such low velocities, the bulk of the stripped hydrogen and helium is embedded within the low-velocity iron of the supernova ejecta. The hydrogen and helium may be visible in the late-time spectra as narrow emission lines.Although most of the stripped material is ejected at low velocities, all the numerical simulations yield a small high-velocity tail. The main sequence, subgiant, and the

The envelope mass of red giant donors in type Ia supernova progenitors

“…The supernova ejecta collides with the envelope of and strips some hydrogen-rich material from the surface of the companion (Marietta et al 2000;Meng et al 2007;Pakmor et al 2008). The stripped-off hydrogenrich material may manifest itself by means of narrow H α emission or absorption lines in later-time spectra of SNe Ia (Chugai 1986;Filippenko 1997).…”

“…The amount of the strippedoff material determines whether or not the narrow hydrogen line can be observed. Marietta et al (2000) ran several highresolution two-dimensional numerical simulations of the collision between the ejecta and the companion. They claimed that about 0.15−0.17 M of hydrogen-rich material is stripped from a MS or a subgiant (SG) companion and 0.5 M from red giant (RG) star.…”

“…They claimed that about 0.15−0.17 M of hydrogen-rich material is stripped from a MS or a subgiant (SG) companion and 0.5 M from red giant (RG) star. Meng et al (2007) used a simple analytic method but a more physical companion model than that used in Marietta et al (2000) to simulate the interaction between SNe Ia ejecta and companions, and found that the minimum mass of the stripped-off material from a MS or SG star is 0.035 M . However, the results of Marietta et al (2000) and Meng et al (2007) did not include confirmation by observations, i.e., no hydrogen line was detected in nebular spectra of some SNe Ia and the upper mass limit to the stripped-off material was set to be 0.02 M (Mattila et al 2005;Leonard 2007).…”

“…Meng et al (2007) used a simple analytic method but a more physical companion model than that used in Marietta et al (2000) to simulate the interaction between SNe Ia ejecta and companions, and found that the minimum mass of the stripped-off material from a MS or SG star is 0.035 M . However, the results of Marietta et al (2000) and Meng et al (2007) did not include confirmation by observations, i.e., no hydrogen line was detected in nebular spectra of some SNe Ia and the upper mass limit to the stripped-off material was set to be 0.02 M (Mattila et al 2005;Leonard 2007). Pakmor et al (2008) used a more physical companion model than and a similar numerical simulation to that of Marietta et al (2000) to recalculate the interaction between the supernova ejecta and companion.…”

Type Ia supernovae: spectroscopic surprises

“…And if the mass ejection was Chandraskhar, why was the luminosity low? One possibility (see the chapter by Kasen) is that SN 2002cx was a low-luminosity SN 1991bg-like event, viewed right down the hole in the ejecta caused by the presence of the donor star (Marietta, Burrows, & Fryxell 2000).…”